Gas-liquid separator for freeze dryer and refrigerating system

Abstract

The utility model provides a gas-liquid separator and a refrigerating system for a freeze dryer, and the gas-liquid separator comprises a barrel body, a gas inlet pipe, a cooling port, a gas return pipe, an oil suction pipe, a subcooler, a hot gas pipe and a distributor, the refrigerating system comprises a compressor, a condenser, a high-pressure liquid storage device, a cold needing end, a gas-liquid separator, a supercooling liquid supply valve, a liquid supply valve, a cooling liquid supply valve, a cooling expansion valve, a hot gas bypass valve and a pressure reducing valve. According to the utility model, the gas-liquid separator is used as a carrier and is matched with a corresponding system and control to achieve the purpose. And during large-load operation, a high-pressure liquid refrigerant is introduced into the gas-liquid separator to exchange heat with low-temperature gas returned by the cold-needing end, so that the supercooling degree is improved, and the economical efficiency of system operation is improved. During small-load operation, high-temperature exhaust gas introduced into the compressor is directly mixed with returned low-pressure liquid refrigerant, so that the high-temperature exhaust gas is gasified, and the operation working condition is improved. A high-pressure liquid refrigerant is introduced into a pipeline through which return air at the end needing to be cooled enters the gas-liquid separator, and the high-pressure liquid refrigerant is sprayed into the return air to cool the return air after steam sterilization.

Description

Technical Field

[0001] The utility model relates to the field of freeze dryer refrigeration systems, in particular to a gas-liquid separator and a refrigeration system for a freeze dryer. Background Art

[0002] The refrigeration system is a key component of the freeze dryer. Throughout a complete freeze-drying cycle, the refrigeration system operates under variable operating conditions and loads, often with wide, even extreme, variations. Therefore, a gas-liquid separator is typically included in the freeze dryer's refrigeration system to separate the low-pressure gas-liquid two-phase refrigerant returning from the cold end, protecting the compressor from liquid hammer damage. Furthermore, to improve economic efficiency during high-load operation and improve operating conditions at low temperatures, the high-temperature, high-pressure refrigerant liquid is passed through the gas-liquid separator to further reduce its temperature and increase subcooling. This also heats the return air from the evaporator to increase superheat at low temperatures.

[0003] However, the current freeze dryer refrigeration system still has some problems. On the one hand, when the refrigeration load is extremely low in the late stage of freeze drying, the refrigeration condition of the freeze dryer will deteriorate rapidly and uncontrollably, and excessive liquid will accumulate in the gas-liquid separator, resulting in poor system operation economy, liquid in the compressor return air, and deterioration of the compressor lubricating oil, thus affecting the reliability and service life of the equipment. This is particularly prominent in freeze dryers using refrigerant direct expansion cold traps.

[0004] On the other hand, for some production freeze dryers that need to have sterilization functions, such as for medicines, if they are put into the next cycle too quickly after steam sterilization, the return air temperature of the refrigeration system will be too high, causing the lubricating oil to deteriorate, the compressor to be easily damaged and abnormally worn, and ultimately affecting the reliability and life of the equipment. Utility Model Content

[0005] In order to solve the problems of low equipment reliability, long life loss and poor operation economy when the freeze dryer is operated at low load or after steam sterilization in the prior art, the utility model provides a gas-liquid separator and a refrigeration system for the freeze dryer;

[0006] The utility model provides a freeze dryer gas-liquid separator and a refrigeration system that adopts the following technical solutions:

[0007] A gas-liquid separator for a freeze dryer comprises a cylinder, an air inlet pipe, a cooling port, an air return pipe, an oil extraction pipe, a supercooler, a hot air pipe and a spreader; an air inlet pipe is provided on the top of the cylinder, an air outlet of the air inlet pipe passes through the top wall of the cylinder and enters the interior of the cylinder, and a cooling port is provided on the portion of the air inlet pipe located outside the cylinder; an air return pipe is provided inside the cylinder, the air return pipe is U-shaped, the air outlet of the air return pipe passes through the top wall of the cylinder and extends to the outside of the cylinder, and the air return pipe is U-shaped. An oil suction pipe is provided at the lowest point, one end of the oil suction pipe is connected to the return air pipe, and the other end of the oil suction pipe extends to the bottom of the cylinder; a subcooler is provided inside the cylinder, and the input and output ends of the subcooler extend to the outside of the cylinder through the bottom wall of the cylinder; a hot air pipe is provided inside the cylinder, one end of the hot air pipe is provided at the lower part of the cylinder and is connected to a distributor, an exhaust hole is provided on the outer surface of the distributor, and the other end of the hot air pipe passes through the side wall of the cylinder and extends to the outside of the cylinder.

[0008] Furthermore, the air inlet of the return air pipe is staggered with the air outlet of the air inlet pipe, the air outlet of the air inlet pipe is arranged in the upper middle part of the cylinder, and the air inlet of the return air pipe is arranged in the upper part of the cylinder at a position higher than the air outlet of the air inlet pipe.

[0009] Furthermore, the U-shaped bend of the air return pipe is arranged at the lower part of the cylinder body near the bottom wall.

[0010] Furthermore, the air outlet of the air inlet pipe and the air inlet of the air return pipe are both beveled.

[0011] Furthermore, the supercooler is spiral-shaped and is arranged at the lower part of the cylinder.

[0012] A refrigeration system, comprising a compressor, a condenser, a high-pressure liquid storage, a cooling end, and also comprising any one of the freeze dryer gas-liquid separators described above; the return air pipe of the gas-liquid separator is connected to the input port of the compressor, the output port of the compressor is connected to the condenser, the condenser is connected to the high-pressure liquid storage, a subcooling branch and a return air cooling branch are provided between the high-pressure liquid storage and the gas-liquid separator, the high-pressure liquid storage is connected to the input end of the subcooler through the subcooling branch, a subcooling liquid supply valve is provided in the subcooling branch, and the subcooling valve is provided. The output end of the cooler is connected to the input port of the cooling end, the output port of the cooling end is connected to the air inlet pipe of the gas-liquid separator, the high-pressure liquid reservoir is connected to the cooling port on the air inlet pipe through the return air cooling branch, and a cooling liquid supply valve and a cooling expansion valve are provided in the return air cooling branch; a liquid supply branch is provided between the high-pressure liquid reservoir and the cooling end, and a liquid supply valve is provided in the liquid supply branch. The liquid supply branch forms a parallel pipeline with the supercooling branch, and the liquid supply branch is connected to the input port of the cooling end in parallel with the output end of the supercooler.

[0013] Furthermore, a hot gas bypass branch is provided between the compressor and the gas-liquid separator, a hot gas bypass valve and a pressure reducing valve are provided in the hot gas bypass branch, and the output port of the compressor is connected to the hot gas pipe through the hot gas bypass branch.

[0014] Furthermore, the cooling end includes a cold trap, a front box heat exchanger, a cold trap liquid supply valve, a cold trap expansion valve, a check valve, a front box liquid supply valve and a front box expansion valve; the output end of the supercooler is connected in parallel with the liquid supply branch and is respectively connected to the cold trap liquid supply valve and the front box liquid supply valve to form a parallel pipeline, the cold trap liquid supply valve is connected to the cold trap expansion valve, the cold trap expansion valve is connected to the input end of the cold trap, the output end of the cold trap is connected to the input end of the check valve, the front box liquid supply valve is connected to the front box expansion valve, the front box expansion valve is connected to the input end of the front box heat exchanger, the output end of the front box heat exchanger is connected in parallel with the output end of the check valve and is connected to the air inlet pipe of the gas-liquid separator.

[0015] In summary, the beneficial effects of the present invention are as follows:

[0016] The utility model uses a gas-liquid separator as a carrier, and by setting a supercooling branch, a return air cooling branch, a liquid supply branch, and a hot gas bypass branch, and being equipped with corresponding systems and controls, it is possible to switch between different working modes under different working conditions of the freeze dryer, thereby improving the operating economy of the freeze dryer and improving the working conditions of its refrigeration system during low-load operation, and greatly improving the reliability and life of the freeze dryer compressor.

[0017] By setting up a supercooling branch, the cooling capacity can be increased and the economic efficiency of the system operation can be improved when a large amount of cooling is required at the cooling end.

[0018] By setting up a liquid supply branch, when the load on the cooling end decreases, the refrigerant can be controlled to flow through the liquid supply branch and directly supply the cooling end.

[0019] By setting up a hot gas bypass branch, when the refrigeration load of the freeze dryer is extremely low, the refrigerant accumulated in the gas-liquid separator can be vaporized and brought back to the system circulation with the help of the high-temperature exhaust gas of the compressor, thereby increasing the suction superheat of the compressor to avoid liquid hammer, improving the operating conditions of the compressor, avoiding the low temperature of the cold end and the deterioration of the compression ratio, thereby improving the economy of the system operation, avoiding the deterioration of the lubricating oil, and improving the reliability of the compressor.

[0020] By setting up a return air cooling branch, the suction temperature of the compressor can be lowered when the refrigeration system is restarted for cooling after the freeze dryer is steam sterilized, avoiding the deterioration of the lubricating oil and the failure and excessive wear of the compressor, thereby improving the reliability and life of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cross-sectional schematic diagram of the gas-liquid separator of the utility model;

[0022] Figure 2 This is a front cross-sectional schematic diagram of the gas-liquid separator of the utility model;

[0023] Figure 3 This is an enlarged schematic diagram of the structure of the diffuser of the utility model;

[0024] Figure 4 This is a schematic diagram of the refrigeration system of the present utility model.

[0025] As shown in the picture:

[0026] Gas-liquid separator: 101-inlet pipe, 102-cooling port, 103-return air pipe, 104-cylinder, 105-hot air pipe, 106-distributor, 107-subcooler, 108-oil extraction pipe;

[0027] Refrigeration system: 1- compressor, 2- condenser, 3- high-pressure liquid receiver, 4- cold trap expansion valve, 5- cold trap, 6- front box expansion valve, 7- front box heat exchanger, 8- check valve, 9- gas-liquid separator, 10- subcooling liquid supply valve, 11- front box liquid supply valve, 12- cold trap liquid supply valve, 13- liquid supply valve, 14- hot gas bypass valve, 15- pressure reducing valve, 16- cooling liquid supply valve, 17- cooling expansion valve, 18- subcooling branch, 19- return air cooling branch, 20- liquid supply branch, 21- hot gas bypass branch. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 -Attached Figure 4 The utility model is further described in detail:

[0029] The present invention discloses a gas-liquid separator and a refrigeration system for a freeze dryer. Figure 1 、 Figure 2 、 Figure 3As shown, the gas-liquid separator 9 for a freeze dryer of the present invention comprises a cylinder 104, an air inlet pipe 101, a cooling port 102, an air return pipe 103, an oil extraction pipe 108, a supercooler 107, a hot air pipe 105, and a distributor 106; the cylinder 104 of the gas-liquid separator 9 is a vertical pressure vessel. The air outlet of the air inlet pipe 101 passes through the top wall of the cylinder 104 and enters the interior of the cylinder 104. The air outlet of the air inlet pipe 101 is arranged in the middle and upper space of the cylinder 104, and the air outlet is an oblique section. A cooling port 102 is provided on the portion of the air inlet pipe 101 outside the cylinder 104. The cooling port 102 is a hollow tube, and the refrigerant can enter the air inlet pipe 101 through the cooling port 102. An air return pipe 103 is provided inside the cylinder 104. The air outlet of the air return pipe 103 extends through the top wall of the cylinder 104 and out of the cylinder 104. The air return pipe 103 is U-shaped, with a U-shaped bend at the bottom of the cylinder 104, located closer to the bottom surface. An oil suction pipe 108 is provided at the lowest point of the U-shaped bend in the air return pipe 103. One end of the oil suction pipe 108 is located at the bottom of the cylinder 104, just as it touches the bottom surface, and the other end opens into the air return pipe 103. When gas flows through the air return pipe 103, a siphon effect is created, carrying the lubricating oil accumulated at the bottom of the cylinder 104 back to the compressor 1 along with the intake air. The inlet of return air pipe 103 is staggered from the outlet of inlet pipe 101 and is located in the upper space of cylinder 104, higher than the outlet of inlet pipe 101, with an oblique cut surface. A subcooler 107 is located in the lower space of cylinder 104, through which high-pressure liquid refrigerant circulates. Subcooler 107 is spiral-shaped, with its input and output extending through the bottom wall of cylinder 104 and out of the cylinder. One end of hot air pipe 105 extends into the lower portion of cylinder 104, and its lower end is a distributor 106. Exhaust holes are evenly distributed on the outer surface and the lower and middle portions of both end surfaces of distributor 106. The other end of hot air pipe 105 extends through the side wall of cylinder 104 and out of the cylinder.

[0030] The refrigeration system is equipped with a high-pressure liquid accumulator 3, which is used to collect and store the refrigerant condensed into liquid in the condenser 2. A refrigerant subcooling branch 18 is provided between the high-pressure liquid accumulator 3 and the gas-liquid separator 9, and a subcooling liquid supply valve 10 is installed in the refrigerant subcooling branch 18. When the freeze-dryer's refrigeration load is high, the high-pressure liquid refrigerant is controlled to enter the gas-liquid separator 9 for further cooling to improve the operating economy of the refrigeration system and increase the suction superheat of the compressor 1. A liquid supply branch 20 is provided between the high-pressure liquid accumulator 3 and the cooling end, and a liquid supply valve 13 is installed in the liquid supply branch 20. When the freeze-dryer's refrigeration load is low, the high-pressure liquid refrigerant is controlled to be supplied directly to the cooling end without passing through the gas-liquid separator 9. A hot gas bypass branch 21 is provided between the compressor 1 and the gas-liquid separator 9, and a hot gas bypass valve 14 and a pressure reducing valve 15 are installed in the hot gas bypass branch 21. When the freeze dryer's refrigeration load is extremely low, low-pressure liquid refrigerant accumulates in the gas-liquid separator 9. This controls the exhaust gas from compressor 1 to flow into the gas-liquid separator 9, heating the low-pressure liquid refrigerant accumulated at the bottom and evaporating it into a gaseous state that is then drawn away by compressor 1. A return air cooling branch 19 is provided between the high-pressure liquid reservoir 3 and the gas-liquid separator 9. This branch is equipped with a cooling liquid supply valve 16 and a cooling expansion valve 17. If the return air temperature from compressor 1 is too high after the freeze dryer undergoes steam sterilization, the return air is cooled.

[0031] The cold end includes the cold trap 5, the front box heat exchanger 7, the cold trap liquid supply valve 12, the cold trap expansion valve 4, the check valve 8, the front box liquid supply valve 11 and the front box expansion valve 6; the output end of the supercooler 107 is connected in parallel with the liquid supply branch 20 and is respectively connected to the cold trap liquid supply valve 12 and the front box liquid supply valve 11 to form a parallel pipeline, the cold trap liquid supply valve 12 is connected to the cold trap expansion valve 4, the cold trap expansion valve 4 is connected to the input end of the cold trap 5, the output end of the cold trap 5 is connected to the input end of the check valve 8, the front box liquid supply valve 11 is connected to the front box expansion valve 6, the front box expansion valve 6 is connected to the input end of the front box heat exchanger 7, and the output end of the front box heat exchanger 7 is connected in parallel with the output end of the check valve 8 and then connected to the air inlet pipe 101 of the gas-liquid separator 9.

[0032] The switch control valve and expansion valve in the refrigeration system of the present invention can be either manually controlled or automatically controlled, and include a subcooling liquid supply valve 10, a liquid supply valve 13, a cooling liquid supply valve 16, a hot gas bypass valve 14, a cooling expansion valve 17, and a pressure reducing valve 15.

[0033] The opening and closing of the subcooling liquid supply valve 10 and the liquid supply valve 13 in the refrigeration system can be controlled based on the suction temperature of the compressor 1. The opening and closing of the hot gas bypass valve 14 and the opening of the pressure reducing valve 15 in the refrigeration system can be controlled and adjusted based on the suction pressure and temperature of the compressor 1, and the liquid level in the gas-liquid separator 9, independently or in combination. The opening and closing of the cooling liquid supply valve 16 and the opening of the cooling expansion valve 17 in the refrigeration system can be controlled and adjusted based on the suction temperature of the compressor 1 or the inlet temperature of the gas-liquid separator 9.

[0034] The present invention is applicable not only to a freeze dryer with a freezing function, but also to a freeze dryer without a freezing function. In this embodiment, a freeze dryer with a freezing function is taken as an example.

[0035] The implementation principle of the embodiment of the utility model is:

[0036] like Figure 4 Figure 1 shows a schematic diagram of a freeze dryer refrigeration system with a refrigeration function. This system typically features two cooling devices: a headbox heat exchanger 7 and a cold trap 5. Cooling is switched and implemented via a headbox liquid supply valve 11, a cold trap liquid supply valve 12, and a headbox expansion valve 6 and a cold trap expansion valve 4.

[0037] After being pressurized by compressor 1, the high-pressure gaseous refrigerant is liquefied in condenser 2 and stored in high-pressure liquid accumulator 3. When the front box heat exchanger 7 and cold trap 5 require a large amount of cooling, the subcooling liquid supply valve 10 is opened, the liquid supply valve 13, the cooling liquid supply valve 16, and the hot gas bypass valve 14 are closed, thereby controlling the high-pressure liquid refrigerant to pass through the cold branch 18 and enter the gas-liquid separator 9. In the subcooler 107 of the gas-liquid separator 9, the high-pressure liquid refrigerant exchanges heat with the low-pressure gaseous refrigerant returning from the cold end, becoming subcooled before being supplied to the cold end, thereby improving the cooling capacity and enhancing the economic operation of the system. When the temperature at the cold end is relatively low, the return gas often contains refrigerant liquid, which can easily cause the suction temperature of compressor 1 to be too low. At this time, the liquid in the low-pressure refrigerant returned by the intake pipe 101 settles to the bottom of the gas-liquid separator 9 under the action of gravity, and exchanges heat with the high-pressure liquid refrigerant in the subcooler 107 to become gas and increase the superheat, thereby preventing the suction temperature of the compressor 1 from being too low, thereby protecting the compressor 1.

[0038] The latter part of the freeze-drying process primarily supplies cold water to the cold trap 5. However, as the moisture content of the material being dried decreases, the load on the cold trap 5 decreases dramatically. At this point, the high-pressure liquid refrigerant becomes overcooled, which is detrimental to system operation. Therefore, it is necessary to close the overcooling liquid supply valve 10 and open the liquid supply valve 13, thereby directing the refrigerant through the liquid supply branch 20 directly to the cooling end, bypassing the gas-liquid separator 9.

[0039] When the freeze-dryer's refrigeration load is extremely low, the liquid supply often exceeds the required amount to maintain the water capture efficiency of the cold trap 5. This has two consequences: a large amount of liquid refrigerant accumulates in the gas-liquid separator 9. Excessive accumulation can easily lead to refrigerant shortages in the high-pressure accumulator 3 and a liquid hammer accident in the compressor 1. Furthermore, it can cause the suction pressure of the compressor 1 to be too low, which in turn causes the temperature of the cold trap 5 to be too low, resulting in poor system operation efficiency. This also increases the compression ratio of the compressor 1, thereby deteriorating its performance. The high compression ratio also causes the compressed exhaust temperature to be too high, affecting the reliability and lubrication performance of the compressor 1. Therefore, it is necessary to open the hot gas bypass valve 14 to direct the high-temperature exhaust gas from the compressor 1 into the hot gas bypass branch 21. After throttling and reducing the pressure of the pressure reducing valve 15, the hot gas pipe 105 feeds the distributor 106 at the bottom of the gas-liquid separator 9. After sufficient heat exchange with the low-pressure liquid refrigerant accumulated at the bottom, the resulting low-pressure refrigerant vapor is drawn into the compressor 1 through the return pipe 103. In this way, the refrigerant accumulated in the gas-liquid separator 9 is vaporized with the help of the high-temperature exhaust gas of the compressor 1 and brought back to the system circulation. At the same time, the suction superheat of the compressor 1 is improved to avoid liquid hammer. Furthermore, the operating conditions of the compressor 1 are improved, and the low temperature of the cold trap 5 and the deterioration of the compression ratio are avoided, thereby improving the economy of the system operation, avoiding the deterioration of the lubricating oil, and improving the reliability of the compressor 1.

[0040] When the freeze dryer is re-started after steam sterilization, the refrigeration system is opened, the liquid supply valve 13 is opened, the subcooling liquid supply valve 10 and the hot gas bypass valve 14 are closed to reduce the temperature. If the return air temperature at the cold end is too high, the cooling liquid supply valve 16 is opened, and the high-pressure liquid refrigerant becomes low-pressure liquid refrigerant after passing through the cooling expansion valve 17. It is sprayed into the intake pipe 101 through the cooling port 102 and mixed with the return air to reduce the temperature. The resulting mixed refrigerant passes through the gas-liquid separator 9 and is sucked into the compressor 1. This reduces the suction temperature of the compressor 1, avoids the deterioration of the lubricating oil and the failure and excessive wear of the compressor 1, and improves the reliability and life of the compressor 1.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. The various components mentioned in the present invention are common technologies in the existing field. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in this utility model is defined by the appended claims and their equivalents.

Claims

1. A gas-liquid separator for a freeze dryer, characterized in that: The invention comprises a cylinder (104), an air inlet pipe (101), a cooling port (102), an air return pipe (103), an oil extraction pipe (108), a supercooler (107), a hot air pipe (105) and a spreader (106); an air inlet pipe (101) is provided on the top of the cylinder (104); an air outlet of the air inlet pipe (101) passes through the top wall of the cylinder (104) and enters the interior of the cylinder (104); a portion of the air inlet pipe (101) located outside the cylinder (104) is provided with a cooling port (102); an air return pipe (103) is provided inside the cylinder (104); the air return pipe (103) is in a "U" shape; an air outlet of the air return pipe (103) passes through the top wall of the cylinder (104) and extends outside the cylinder (104); the air return pipe (103) ) An oil extraction pipe (108) is provided at the lowest point of the U-shaped bend, one end of the oil extraction pipe (108) is connected to the return air pipe (103), and the other end of the oil extraction pipe (108) extends to the bottom of the cylinder (104); a subcooler (107) is provided inside the cylinder (104), and the input end and the output end of the subcooler (107) pass through the bottom wall of the cylinder (104) and extend outside the cylinder (104); a hot air pipe (105) is provided inside the cylinder (104), one end of the hot air pipe (105) is provided at the lower part of the cylinder (104) and is connected to a distributor (106), an exhaust hole is provided on the outer surface of the distributor (106), and the other end of the hot air pipe (105) passes through the side wall of the cylinder (104) and extends outside the cylinder (104).

2. A gas-liquid separator for a freeze dryer according to claim 1, characterized in that: The air inlet of the return air pipe (103) is staggered with the air outlet of the air inlet pipe (101), the air outlet of the air inlet pipe (101) is arranged at the upper middle part of the cylinder (104), and the air inlet of the return air pipe (103) is arranged at a position higher than the air outlet of the air inlet pipe (101) at the upper part of the cylinder (104).

3. A gas-liquid separator for a freeze dryer according to claim 2, characterized in that: The U-shaped bend of the air return pipe (103) is arranged at the lower part of the cylinder (104) near the bottom wall.

4. A gas-liquid separator for a freeze dryer according to claim 3, characterized in that: The air outlet of the air inlet pipe (101) and the air inlet of the air return pipe (103) are both beveled.

5. A gas-liquid separator for a freeze dryer according to claim 4, characterized in that: The supercooler (107) is spiral-shaped and is arranged at the lower part of the cylinder (104).

6. A refrigeration system comprising a compressor (1), a condenser (2), a high-pressure liquid receiver (3), and a cold end, characterized in that: It also includes the gas-liquid separator for the freeze dryer according to any one of claims 1 to 5; the return air pipe (103) of the gas-liquid separator (9) is connected to the input port of the compressor (1), the output port of the compressor (1) is connected to the condenser (2), the condenser (2) is connected to the high-pressure liquid reservoir (3), a subcooling branch (18) and a return air cooling branch (19) are provided between the high-pressure liquid reservoir (3) and the gas-liquid separator (9), the high-pressure liquid reservoir (3) is connected to the input end of the subcooler (107) through the subcooling branch (18), a subcooling liquid supply valve (10) is provided in the subcooling branch (18), and the output end of the subcooler (107) is connected to the input end of the cooling end. The output port of the cooling end is connected to the air inlet pipe (101) of the gas-liquid separator (9); the high-pressure liquid storage device (3) is connected to the cooling port (102) on the air inlet pipe (101) through a return air cooling branch (19); a cooling liquid supply valve (16) and a cooling expansion valve (17) are provided in the return air cooling branch (19); a liquid supply branch (20) is provided between the high-pressure liquid storage device (3) and the cooling end; a liquid supply valve (13) is provided in the liquid supply branch (20); the liquid supply branch (20) and the supercooling branch (18) form a parallel pipeline; the liquid supply branch (20) is connected in parallel with the output port of the supercooler (107) and then connected to the input port of the cooling end.

7. A refrigeration system according to claim 6, characterized in that: A hot gas bypass branch (21) is provided between the compressor (1) and the gas-liquid separator (9), a hot gas bypass valve (14) and a pressure reducing valve (15) are provided in the hot gas bypass branch (21), and the output port of the compressor (1) is connected to the hot gas pipe (105) via the hot gas bypass branch (21).

8. A refrigeration system according to claim 7, characterized in that: The cooling end includes a cold trap (5), a front box heat exchanger (7), a cold trap liquid supply valve (12), a cold trap expansion valve (4), a check valve (8), a front box liquid supply valve (11) and a front box expansion valve (6); the output end of the subcooler (107) is connected in parallel with the liquid supply branch (20) and is respectively connected to the cold trap liquid supply valve (12) and the front box liquid supply valve (11) to form a parallel pipeline, and the cold trap liquid supply valve (12) and the cold trap expansion valve (4) are connected in parallel. The cold trap expansion valve (4) is connected to the input end of the cold trap (5), the output end of the cold trap (5) is connected to the input end of the check valve (8), the front box liquid supply valve (11) is connected to the front box expansion valve (6), the front box expansion valve (6) is connected to the input end of the front box heat exchanger (7), and the output end of the front box heat exchanger (7) and the output end of the check valve (8) are connected in parallel and then connected to the air inlet pipe (101) of the gas-liquid separator (9).

Images